Copyright © 2015  Grand Rapids Technologies, Inc.

Electronic Flight Instrumentation for Experimental Aircraft Since 1991

G-Meter

The G-meter is one of those little hidden features that is easy to configure and can eliminate the need for a separate dedicated instrument.




What is it?

It simply measures the G-loading of the airplane based on forces measured by the accelerometers inside the AHRS. It’s displayed to the right of the airspeed tape on the Primary Flight Display.

How do I turn it on?

In the Set Menu, go to the Primary Flight Display page. There are several G-Meter options near the bottom of the screen. These are:

G-Meter Mode- Choose how to display it on the Primary Flight Display.

G-Meter Maximum- Sets the maximum positive G-loading on the scale

G-Meter Minimum- Sets the minimum negative G-loading on the scale

G-Meter Caution Max-Positive G-load caution threshold-Turns yellow beyond this value

G-Meter Caution Min- Negative G-load caution threshold- Turns yellow beyond this value

Auto G-Meter High Threshold- Displays the G-meter on the PFD in “Auto” setting when this positive-G value is exceeded

Auto G-Meter Low Threshold- Displays the G-meter on the PFD in “Auto” setting when this negative value is exceeded

To turn on the G-meter, select an option on the G-Meter Mode setting:

Off- Does not display. Note that even when the G-Meter Mode is set to “Off,” all G force data is recorded during data logging.

On- Displays all the time

On with Min/Max- Displays all the time with the minimum and maximum Gs experienced during the flight

Auto- Comes on if a preset Auto G-Meter High or Low Threshold is exceeded. This allows it to replace Trim Indicators temporarily until the G limits settle below the threshold. (See Trim Indicator notation below…)

How do I set it up?

Enter the maximum (positive limit) and minimum (negative limit) of your aircraft in the G-Meter Minimum and Maximum settings. Set the Caution limits the same way; the G meter turns red if the Max/Min limits are exceeded, and turns yellow if the Caution limits are exceeded. Your aircraft designer may have established caution levels, or you can choose your own.

But I have Trim Indicators on my EFIS, and they’re already displayed in that spot!

Space on the PFD is limited, and the best place for the Trim indicators happens to be the same place the G meter resides. The good news is, when you need the trim indicator, you are usually on the ground. When you need the G-meter, you are maneuvering, and any trim settings you make will probably be done by feel anyway. The G-Meter Mode “Auto” setting will automatically make the G meter appear in place of the trim indicator when the Auto G-Meter Max and Min Threshold limits are exceeded in flight.

Data Logging

G-force data is recorded with all of the other AHRS data during a demo recording. For instructions on how to record a permanent record of your G readings, see the Flight Data Recording Feature of the Week  for automatic recording of flight data.  

Any limitations?

Just the limitations of the AHRS:  +/- 10 G of acceleration. Yikes!